The tenants above me

[Strad]

From time to time, regardless how many times I've told him to be careful, the tenant live above me spill water from his sink and leak right down to my bedroom. The water leaking not only caused damage to my ceiling panels and stained my bedding, but also it took long time to clean the dirt that came alone with the water.
What measure should I take to make the guy above me to be more responsible? Any advice please!
Sincerely
Strad,
New York City
mystrad168@hotmail.com